12.2.3 Time Required For Output And Accuracy Of The Analog Value Output - Siemens SIMATIC S5-90U System Manual

Analog Value Processing

12.2.3 Time Required for Output and Accuracy of the Analog Value Output

The Table below shows the various possibilities for calculating the time required for the output of an
analog value.
Table 12-16. Maximum Duration for Outputting an Analog Value
Possibilities for Outputting
Analog Values
Write analog values into the
process image
Write analog values to the
outputs via direct I/O access
The time values for the runtimes specified in Table 12-16 are given in the Operations List
(see Appendix A), in the Technical Specifications for the S5-95U (see Appendix B) and Chapter 6.
12-12
Maximum Duration
of Output to
Onboard I/Os
• Using the T QW
operation:
Cycle time from the
T QW ... operation to
the end of the cycle
+ operating system
runtime
• Using FB251:
Cycle time starting from
the call of FB251
+ execution time of
FB251
• Using the T PW 40
operation:
Execution time of
operation +
conversion time
S5-90U/S5-95U
Maximum Duration
of Output to
External I/Os
• Using the T QW ... operation:
No. of channels on module
x Conversion time per
output
+ Cycle time from
T QW ... operation
to end of cycle
+ Operating system
runtime
+ PI transfer time
• Using FB251:
No. of channels on module
x Conversion time per
output
+ Cycle time from
T QW ... operation
to end of cycle
+ Exec. time of FB251
+ Oper. system runtime
+ PI transfer time
Not possible
EWA 4NEB 812 6115-02b